Migrant crisis: The Syrian migrants left in Turkey

There are signs that the European Union's efforts to stop the flow of migrants into Europe are beginning to have a significant impact.

Numbers arriving from Turkey onto the Greek islands were down about 90% in April compared with the previous month following a deal struck between the EU and Turkey.

However, political pressures mean the deal is now looking increasingly vulnerable, as BBC Europe Editor Gavin Hewitt reports from Izmir.